I. FILICES. 
379 
21. NEPHROLEPIS, Schott. 
Rhizome creeping or short or 0. — Fronds coriaceous, pinnate. Pinnae 
jointed on the rachis, deciduous, with minute white waxy dots on the upper 
surface. Sori dorsal, on the tip of the upper branch of a vein. Involucre 
flat, cordate reniform or lunate, attached by a broad base. 
A small tropical or subtropical genus. 
1. N. tuberosa, Presl. Rhizome scarcely any; roots of long wiry 
fibres, bearing ovoid or oblong scaly tubers. Fronds tufted, 1-3 ft. long, 
linear-lanceolate, acuminate, pinnate ; stipes stout and rachis with deciduous 
scales ; pinnules numerous, close set, horizontal, -g-l in. long, oblong, obtuse, 
truncate cordate or obliquely auricled at the base, straight or falcate, lower 
shorter. Sori halfway between the costa and margin ; involucre firm, reni- 
form, brown, black towards the base.— Hook. Sp. Fil. iv. 151. 
Northern Island : hot springs near Waikati, Dr. Hochstetter and Sinclair. A most 
abundant tropical fern, also found in the warmer parts of Australia. The tubers are eaten in 
India. 
22. POLYPODIUM, Linn. 
Rhizome erector creeping or 0. — Fronds tufted or not, simple or compound. 
Venation various. Sori globose (sometimes oblong in P. Grammitidis) . In- 
volucre 0. 
As above defined, this is the largest genus of ferns. It is broken up into many genera by 
most authors, but these are united by so many ambiguous species, that it is difficult to retain 
any of them. Many of the species are naturally referable to genera in which there is 
always an involucre ; thus P. rugulosum passes into Hypolepis tenui.folia ; P. pennigerum 
is a Ne.phr odium, without the involucre ; and P. sylvaticum approaches Aspidium aculeatum, 
very closely, in habit and other respects. 
I. Veins usually free. Sori rounded, linear or oblong, placed on the ends, rarely on the 
middle of the veinlets. 
a. Frond simply pinnate or pinnatifidly divided. 
Rhizome short, creeping, scaly. Frond quite entire. Sori oblong 
or linear 1. P. austral e. 
Rhizome very short, scaly. Frond pinnatifid. Sori round or oblong 2. P . Grammitidis. 
Rhizome long, slender, climbing. Fronds pendulous, pinnate, gla- 
brous 3. P. tenellum. 
j8. Frond 2-i-pinnate. 
Rhizome short, stout, erect. Fronds tufted, erect, lanceolate ; pin- 
nules spinulose 4. P. sylvaticum. 
Rhizome long, stout, creeping. Frond deltoid, glandular ; pinnules 
obtuse 5. P. rugulosum. 
II. Veins all free except those next the margin, which meet or almost meet (Goniopteris) . 
Rhizome stout, erect. Frond pinnate, membranous, glabrous . . 6. P. pennigerum. 
III. Veins anastomosing, hidden in the frond which is densely covered with stellate hairs 
( Niphobolus ). 
Rhizome creeping, scaly. Frond entire 1- P. rupestre. 
IV. Veins anastomosing, with free veinlets in the areoles. Fronds glabrous {Phymatodes) . 
Rhizome very short. Fronds tufted, lanceolate, acuminate, quite 
entire 8. P. Cunninghami. 
